Apparatus for jet air cooling of tires during postinflation

ABSTRACT

Various forms of apparatus for cooling pneumatic tires as they are removed from the press following the mold cycle and are subjected to a postinflation cycle outside the press, are disclosed. The basic apparatus includes means defining a cooling zone in which each tire being cooled may be axially received. The cooling zone is provided with orifice means arranged coextensively with its peripheral boundary to enable cooling air to be directed in jet form against the tire in its shoulder regions simultaneously along the entire circumference thereof, preferably so as to be incident initially directly against the shoulder regions of the tread. By proper choice of the blower means, the sizes, distribution and arrangement of the orifices, and the sizes and pressure drop characteristics of the duct system, the airflow conditions can be controlled to deliver a desired tire to air heat transfer coefficient ranging from about 15 to about 70 B.t.u./hr./sq. ft./* F. over the surface of the tire so as to ensure that, subject to appropriate adjustment of the duration of the jet air cooling relative to the duration of the in-mold heating, the finished tire is characterized by an optimized set of circumferentially substantially uniform thermal, physical and geometrical properties. This abstract is not to be taken either as a complete exposition or as a limitation of the present invention, however, the full nature and extent of the invention being discernible only by reference to and from the entire disclosure.

United States Patent I Hugger et a1.

[ 51 Feh.29,1972

[54] APPARATUS FOR JET AIR COOLING OF TIRES DURING POSTINFLATION [72]lnventors: Richard H. Hugger, Ridgewood; George C. Huang, Kinnelon, bothof NJ.

[73] Assignee: Uniroyal, Inc.

[22] Filed: May 21, 1969 [21] Appl.No.: 851,112

A Related US. Application Data [62] Division of Ser. No. 596,114, Nov.22, 1966, aban- Primary Examiner-J. Howard Flint, .l r. Attorney-NorbertP. Holler [5 7] ABSTRACT Various forms of apparatus for coolingpneumatic tires as they are removed from the press following the moldcycle and are subjected to a postinflation cycle outside the press, aredisclosed. The basic apparatus includes means defining a cooling zone inwhich each tire being cooled may be axially received. The cooling zoneis provided with orifice means arranged coextensively with itsperipheral boundary to enable cooling air to be directed in jet formagainst the tire in its shoulder regions simultaneously along the entirecircumference thereof, preferably so as to be incident initiallydirectly against the shoulder regions of the tread. By proper choice ofthe blower means, the sizes, distribution and arrangement of theorifices, and the sizes and pressure drop characteristics of the ductsystem, the airflow conditions can be controlled to deliver a desiredtire to air heat transfer coefficient ranging from about 15 to about 70B.t.u./hr./sq. ft./ F. over the surface of the tire so as to ensurethat, subject to appropriate adjustment of the duration of the jet aircooling relative to the duration of the inmold heating, the finishedtire is characterized by an optimized set of circumferentiallysubstantially uniform thermal, physical and geometrical properties. Thisabstract is not to be taken either as a complete exposition or as alimitation of the present invention, however, the full nature and extentof the invention being discernible only by reference to and from theentire disclosure.

17 Claims, l5 Drawing Figures PAIENTEDFEBZB I972 3,645,660

SHEET 2 [IF 9 E 2 4 sea/r65 cJ/VANG BY mun/4% ATTORNEY APPARATUS FOR JETAIR COOLTNG OF TIRES DURING POSTKNFLATHON This application is a divisionof Application Ser. No. 596,114, filed Nov. 22, 1966, now abandoned.This invention relates to improvements in the production of pneumatictires and especially in the molding and the postinflation stages of themanufacture thereof.

For the tire industry, striving to meet quality standards for pneumatictires which are becoming ever more stringent, the production of tireswhich are highly resistant to tread groove cracking and are alsocircumferentially uniformly dimensioned and cured is a matter of vitalimportance. To this end, pneumatic tires, immediately after beingremoved from the press or mold and while cooling down from therelatively high curing temperatures utilized in the press, are generallymounted on a suitable airtight rim or chuck structure and internallyinflated by air to a pressure of about 30 to 50 psi. or more, themaximum pressure in any given case basically depending on the size andtype of the tire involved. This technique is universally known aspostinflation.

in actual practice, the tires on the postinflation equipment are almostinvariably cooled by open air natural convection, resulting from theirbeing exposed to the ambient atmosphere surrounding such equipment. Openair natural convection cooling has been found to be somewhatunsatisfactory, however, since not only is the rate of coolingrelatively low due to the low heat transfer coefficient of stagnant orslow moving air, but it is also not uniform over all portions of eachtire. This will be readily understood when it is considered thatpostinflation equipment is always located as near the tire curingpresses as possible, whereby during postinflation the different parts ofeach tire (for example, the respective regions thereof facing toward andaway from the press) will be exposed to different ambient temperatures,a condition which may be aggravated even further by such unpredictablefactors as drafts in the curing room resulting from opening and closingof windows and doors, existing outside weather conditions, etc.

It is furthermore well known that tires continue to cure even after theyhave been removed from the press and while they are cooling down. it isthen found, however, that a tire subjected to such nonuniform coolingrates is generally circumferentially nonuniformly cured at the locus ofany given radial distance from the axis of the tire. A concomitant ofthis drawback has been the fact that such tires are also found to becharacterized by radial dimensions which are circumferentiallyexcessively nonuniform.

The foregoing considerations apply to all tires reinforced by carcassescomposed of one or more plies of tire cord fabric, irrespective of thenature of the material of which the tire cords are made, i.e., whethersuch material develops substantially no or only negligible shrinkagestresses when subjected to high temperatures (such as cotton, rayon,glass fiber, steel wires, and the like) or whether it does developappreciable shrinkage stresses under high temperatures (such as nylon,polyester, and the like). As to all such pneumatic tires, postinflationhas provided great advances toward the elimination or minimization oftread groove cracking, inservice growth, and other related defects.

Tires made with standard nylon tire cord carcasses, apparently due tothe thermoplastic characteristics of nylon, have nevertheless remainedbeset by the problem of flat spotting, i.e., the tendency of such tiresto develop flat spots when vehicles on which they are mounted are leftstanding for considerable periods of time. Since postinflation has notled to the elimination of this defect, attempts have been made toovercome the problem by the development and use of new tire cordmaterials. Merely by way of example, one such new material, a novel formof nylon recently developed by E. l. du Pont de Nemours & Co. and knowngenerally as nylon-44 or N-44" nylon, gives promise that tiresreinforced by carcasses made of this fiber may no longer be as seriouslytroubled by flat spotting, but tests have shown that nylon-44 carcasstires must be reduced by temperatures on the order of l40-160 F. or lessat the tread-carcass interface in order to reduce the cord shrinkageforces to an acceptable level and permit the post inflation operation tobe terminated. ln this connection, however, tests have also shown thatgenerally in any batch of tires, regardless of thenaturc of the carcass,there will be a better yield of acceptable tires, i.e., tires notdeviating more than a certain amount from preselected standards, whenthese tires are cooled to such relatively low temperatures whileundergoing post inflation.

Although in theory the effectuation of such a temperature reductionoffers no difficulties, in a practical tire manufacturing operation theneed to wait for such a large temperature drop to take place is adisastrous disadvantage, due to the fact that under the standard openair convection cooling procedures, a tire must remain on thepostinflation stand for a period of time roughly equivalent to from twoto three or more full mold cycles to reach a temperature of about l60 F.In modern tire curing rooms, each press is generally associated with itsown postinflation equipment, a dual unit press of any of the major typesused by almost the entire industry thus requiring postinflationequipment able to accommodate the two tires cured during each operatingor mold cycle of the press.

For standard dual (two-chuck) postinflation equipment, therefore, it isan absolute necessity for the tire to cool to the desired temperature ina period of time, i.e., a postinflation cycle, which is at most equal toand preferably somewhat shorter than a single mold cycle, so that thecooled tires can be removed from the postinflation equipment before thenewly cured tires arrive there after being removed from the press. Onthe other hand, in certain types of recently developed quadruplepostinflation equipment provided with two pairs of chucks able toaccommodate four tires at a time, each pair of tires removed from thepress can be permitted to stay on its pair of postinflation chucks for aperiod of time slightly less than two mold cycles in the press.

To the best of our knowledge, no postinflation equipment is presently inuse which is capable of accepting three or more pairs of tires at a timeso as to permit each tire to remain subjected to postinflation for acorrespondingly greater number of mold cycles. In fact, space availablein tire factories at the present time is already so limited that the useof such equipment (which would, of necessity, be extremely bulky) oreven the provision of extra sets of the currently available types ofpostinflation equipment is a practical impossibility.

Various proposals have heretofore been made to accelerate the cooling oftires on postinflation equipment, i.e., to shorten the postinflationcycle, by subjecting such tires to the action of a moving cooling fluid.Representative of one class of these proposals are the techniques andequipment disclosed in Soderquist U.S. Pat. No. 2,963,737, Woodhall U.S.Pat. No. 3,008,180 and Brundage et. al. U.S. Pat. No. 3,065,499, all ofwhich contemplate spraying water over each tire on the post inflationstand. While in theory the heat absorption capacity of water issufiicient to ensure that any tire subjected to a cold water spray wouldbe cooled sufficiently within a period of time somewhat less than onefull mold cycle, this method has not found any substantial acceptance inthe tire industry principally for reasons of space and economyessentially similar to those which have militated against the simpleexpedient of increasing the quantity of available postinflationequipment, viz the problem of where to put the required bulky pumpingmechanisms, liquid handling (supply and drainage) ducts, and relatedequipment for extracting from used water the heat imparted thereto bythe tires being cooled, and the high cost of such systems. Water is alsoquite messy, and its use creates intolerable working conditions in thecuring or press room.

On the other hand, it has also been proposed in Waters et. al. U.S. Pat.No. 3,039,839 to subject a cured tire on a postinflation stand to theaction of a stream of room temperature air which would be blown againstthe tire by means of fans or with the aid of nozzles connected with asource of air under pressure. This approach too has not proved generallysuccessful, even in the special case (to which that patent is primarilyaddressed) of tires reinforced by standard nylon-66 tire cord carcasses,in that it provides no assurance that a nonuniform cooling of differentportions of the tire, as previously explained, can be avoided. In thecase of tires reinforced by nylon-44 cord carcasses, this drawback issupplemented by the fact that the rate of heat transfer attainable bythe Waters et. al. procedure is too low as well.

It is an important object of the present invention, therefore, toprovide means enabling the problems and disadvantages heretoforeencountered in the known methods of cooling pneumatic tires duringpostinflation to be substantially eliminated.

It is also an object of the present invention to provide means renderingthe production of pneumatic tires more economical by enabling therespective full cure cycles of such tires, each consisting of a moldcycle and an immediately subsequent postinflation cycle, to beconsiderably shortened through a shortening of both parts of each curecycle in such a manner that a major proportion of the desired cure stateof the tire is achieved in the mold cycle and the remaining minorproportion in the postinflation or cooling cycle.

Yet another object of the present invention is the provision of novelapparatus for rapidly and in a precisely controlled uniform mannercooling tires made with carcasses of either heat-shrinkable ornonheat-shrinkable fiber tire cord materials during postinflation ofsuch tires.

Generally speaking, as first disclosed in our aforesaid and copendingapplication, during the mold cycle we heat each tire for a predeterminedperiod of time which is less than the duration of a mold cycle requiredfor effecting a full cure of that type of tire, thereby to impart to thetire during the soshortened mold cycle a major proportion of the desiredcure state to be attained in the entire cure cycle, whereupon during theimmediately subsequent postinflation cycle we direct jetlike streams ofcooling air, in predetermined flow patterns and at predeterminedelevated volume flow rates sufficient to deliver a relatively high heattransfer coefficient on the order of from about to 70 B.t.u./hr./sq.ft./ F., to be initially incident against selected regions of the tire,preferably the tread and shoulder regions which are normally thethickest and have the greatest heat-retaining capacity. The airflowconditions are furthermore so chosen that the heat transfer coefficientis automatically adapted to the varying thicknesses of differentsections of the tire, specifically to be higher at the thicker sectionsthan at the thinner ones. The term heat transfer coefficient" as usedherein will be more explicitly defined presently.

To this end, the apparatus according to the present invention includesmeans to define a cooling zone where a tire to be cooled after beingremoved from the press may be received while mounted on postinflationequipment, and orifice means arranged coextensively with the peripheralboundary of the cooling zone to enable the cooling air to be formed intothe desired jetstreams and appropriately directed against a tire whenthe same is located in the cooling zone. The required airflow conditionsare controlled by a proper choice of the blowers, the sizes andcharacteristics of the duct system and the cooling zone, and the sizes,distribution and arrangement of the orifices in the cooling zone.

The cooling air may be taken directly from the curing room atmosphereor, alternatively, may be taken from the outside of the building, and itmay be either at the ambient temperature, generally between about 70 and120 F. in the curing room and possibly somewhat lower outside, or it maybe preliminarily cooled or refrigerated to any desired lowertemperature. The volume flow rate of the air may range from about 500 to1,000 cubic feet per minute in the case of most passenger tires, but ifnecessary, for example in the case of larger tires, correspondinglyhigher volume flow rates, ranging up to as much as 5,000 cubic feet perminute or more, may be employed. The tire when thus' treated is cooledfrom its curing temperature to a temperature in the range of l40-l60 F.at the tread-carcass interface in the shortest possible time andspecifically in less than one full mold cycle.

With respect to nylon-44, actual tests have shown that treated, twistedand solutioned 1260/2 cords of this material having an average preheattension of about 0.070 to 0.10 lb., develop a shrinkage tension atconstant length of about 1.55 lbs/cord when heated to a temperature ofabout 350 F., which is reduced to about 0.3 lb./cord upon cooling to 160F. and to about 0.2 lb./cord upon cooling to F. The beneficial effectwhich a major total cord stress reduction can bring about thus will be.readily understood when it is considered that there are generally about20 cord ends per inch width in each fabric ply of the carcass. Thecontrolled jet air cooling method of the present invention not onlyachieves this result in an extremely short period of time, as previouslystated, but also in such a manner that both the stress reduction and thefinal cure state and dimensional stability are as uniform as possiblethroughout the circumference of the tire being cooled.

The foregoing and other objects, characteristics and advantages of thepresent invention will be more fully understood from the followingdetailed description thereof when read in conjunction with theaccompanying drawings, in which:

FIG. I is a fragmentary side elevational view of a jet air coolingapparatus constructed in accordance with one aspect of the basicprinciples of the present invention and adapted for use in conjunctionwith one type of postinflation equipment;

FIG. 2 is a fragmentary plan view of a part of the cooling apparatusshown in FIG. 1, the view being taken along the line 2-2 in FIG. 1;

FIG. 3 is a fragmentary side elevational view, partly in section, of thejet air cooling apparatus and postinflation equipment shown in FIG. Iwhen activated for a tire-cooling operation;

FIG. 4 is a sectional view taken along the line 4-4 in FIG.

FIG. 5 is a fragmentary,vpartly sectional, plan view, similar to FIG. 2,of a part of a jet air cooling apparatus having a somewhat modifiedconstruction according to the present invention; 7

FIG. 6 is a side elevational view of another form of jet air coolingapparatus constructed to implement the process aspects of the presentinvention and adapted for use in conjunction with a different type ofpostinflation equipment;

FIG. 7 is a fragmentary plan view of the structure shown in FIG. 6, theview being taken along the line 7-7 of FIG. 6;

FIG. 8 is a fragmentary rear elevational view of the structure shown inFIG. 6;

FIG. 9 is a fragmentary vertical section, partly in elevation, throughthe air distributing means of the jet air cooling apparatus shown inFIG. 6, the view being taken along the line 99 in FIG. 10;

FIG. 10 is a sectional view taken along the line l0l0 in FIG. 9;

FIG. 11 is a diagrammatic illustration, similar to FIG. 3, of anothermethod of and apparatus for cooling tires during postinflation inaccordance with the present invention;

FIG. 12 is a fragmentary sectional view taken along the line 12-12 inFIG. 11;

FIG. 13 is a fragmentary sectional view taken along the line l3-l3inFIG. 12;

FIG. 14 is a diagrammatic illustration of yet a further method of andapparatus for cooling postinflated tires in accordance with the presentinvention; and

FIG. 15 is a graphic representation of the advantageous results achievedby the implementation of the tire production improvements of the presentinvention.

Referring now first to FIGS. ii to 4, the jet air cooling apparatus 20according to our invention there shown is designed for use inconjunction with postinflation equipment 2K of the type in which thetire-receiving chuck or rim structure 22 is supported at one end of anam 23 the other end of which is connected at 23a to a support 24 forpivotal swinging movement in a vertical plane. The arm 23 is providedwith a longitudinal duct 25 establishing communication between a tire22a (FIG. 4) in the chuck 22 and a hose 26 to enable air under pressureto be admitted into a tire T, when the latter is mounted on the chuck,so as to inflate the tire. Intermediate its ends, the arm 23 isarticulated at 27 to the free end of a piston rod 28 of a suitabledouble-acting fluid pressure cylinder 29 the blind end of which ispivotally connected at 29a to a support 30. In this manner, thepostinflation equipment 21 may be moved reciprocally between thepositions thereofillustrated in FIGS. 1 and 3.

The jet air cooling apparatus 20 designed, according to this aspect ofthe present invention, to be used with the postinflation equipment 21,comprises a pair of cooling chamber-defining members 31 and 32. Thesemembers are substantially identical in construction and are arranged inmirror image relation to one another, being provided at their facingsides with semicylindrical recesses C and C" (FIG. 1) which, when themembers 31 and 32 are in closed end to end juxtaposition (FIG. 3),define a cylindrical chamber C to accommodate the tire T being cooled.Merely by way of example, the member 31 is stationarily supported in anysuitable manner (not shown) by framework 33, while the member 32 ismovably supported by the framework 33 through the intermediary ofa link34 pivotally connected at 34a to the member 32 and at 34b to a bracket33a of the framework 33. A cable 35 is connected to the member 32 toenable the latter to be raised away from or lowered toward the member31.

As clearly shown in FIGS. 1 to 4, the curved boundary of the recess orchamber section C of member 31 is defined by a semicylindrical wall 36which also constitutes the curved boundary of an essentially U-shapedplenum chamber 37 the opposite boundary of which is constituted by atransverse flat wall 38. In the illustrated form of the invention, thewall 36 is shown as being provided with two pairs of parallel rows ofsmall orifices 39 extending from one end of the wall 36 to the other,and the wall 38 is provided throughout its entire expanse with aplurality of openings 40 (FIGS. 3 and 4) preferably arranged instaggered parallel rows.

The member 31 is further provided with a chamber 41 coextensive with thewall 38. The chamber 41, which is shown as being essentially wedgeshaped, communicates through a duct 42 with one branch 43a of thedischarge side of a suitable blower 43 mounted on a bracket 33b of theframework 33. The intake side of the blower 43 is arranged to draw airfrom any suitable source, preferably the atmosphere in the tire curingroom in which the apparatus 20 is located. The arrangement thus is suchthat air entering the chamber 41 from the duct 42 is distributed overthe wall 38 so as to reach a uniform static pressure by virtue of thephysical parameters of the chamber 41 and thence enters the plenumchamber 37 in a uniform manner, from which it passes at likewise uniformvolume flow rates through the openings 39 into the recess C.

In identical fashion, the recess C" of the member 32 is bounded by asemicylindrically curved wall 44 which is provided with four rows oforifices 45 and also constitutes the curved boundary of a U-shapedplenum chamber 46 the opposite boundary of which is defined by a flatwall 47 provided with a plurality of openings 48 over its entireexpanse. Through the openings 48, the chamber 46 communicates with awedge-shaped chamber 49 which in turn communicates with a flexible duct50 connected to a second branch 43b of the discharge side of the blower43. It will be apparent from FIG. 4 that the respective sets of orifices39 and 45 are so arranged that when the members 31 and 32 are closed todefine the cooling chamber C (FIG. 3), the orifices are disposed in fourcontinuous rows extending circumferentially about the chamber C attransversely spaced locations. Preferably, the spacing of the pairs ofrows of orifices corresponds to the average distance between theshoulder regions of the tires in the range of nominal sizes to betreated in the apparatus 20.

In operation, as soon as a tire T is removed from the press (not shown),mounted on the chuck or rim 22 of the postinflation stand 21 andinflated with air to a suitable internal pressure via the conduits26-25-22a, the cylinder 29 is actuated to retract the piston rod 28,thereby to swing the arm 23 from its position shown in FIG. 1 to itsposition shown in FIG. 3, until one-half of the tire is disposed withinthe confines of the semicircular recess C defined by the wall 36 of themember 31. The member 32 is now lowered through the cable 35 into theposition shown in FIG. 3, so that the tire T is fully confined withinthe cooling zone defined by the cylindrical chamber C. With the blower43 working, the cooling air, which in the illustrated preferred case isat the curing room temperature, normally on the order of about to I 10F. (although it may be somewhat higher or lower), enters the chambers 41and 49 and thence, due to the shape of these chambers and the provisionof the perforated distribution walls 38 and 47, enters the respectiveplenum chambers 37 and 46, i.e., the distribution zone defined by thesechambers, at a uniform static pressure. From the chambers 37 and 46,this air flows uniformly at a relatively high volume flow rate throughthe orifices 39 and 45 (see FIG. 4) against the tread of the tire T,playing principally against the shoulder regions of the tire (which areusually the thickest and thus the most heat retentive) and thence inpart over the crown center region and in part over the sidewalls of thetire, the spent air leaving the cooling chamber via the open sidesthereof. The details of the operating conditions employed to ensure thatthis arrangement enables the tire T to be cooled from the curingtemperature to a temperature of about l40l60F. at the tread-carcassinterface at a period of time which is shorter than the duration of anormal full cure mold cycle for that type of tire will be more fullyexplained hereinafter in conjunction with the description of the processaspects ofthe present invention.

As previously indicated, although the use of the air in the curing roomis preferred, it would be possible to use air piped in from the outsideor from a suitable precooling or refrigerating device. A central airdistribution system may be utilized as the air source, ifdesired. In anyevent, the basic requirement is that the air temperature be lower thanthe temperature to which the tire is to be cooled. For reasons whichwill presently become clear, the time of exposure of the tire to thecooling airflow may have to be adjusted in dependence on the airtemperature.

In accordance with another aspect of the present invention (see FIG. 5),the jet air cooling apparatus 20 may be modified somewhat through theuse ofa pair of cooling chamber-defining members 51 (only one is shown)in lieu of the members 31 and 32 shown in FIGS. 1 to 4. Each such member51 differs from either of the members 31 and 32 in that thesemicylindrical wall 52 (which corresponds to the walls 36 and 44) isprovided at its opposite sides with a pair of generally radiallyinwardly and axially outwardly extending wall portions 53 and 54. Thecooling chamber section defined by the member 51 thus is somewhat troughshaped (rather than semicylindrical as are the chamber sections C andC). An internal plenum chamber 55 in the member 51 is bounded at thefront by the wall 52-53-54, and, like the chambers 37 and 46, is boundedat the rear by a distribution wall (not shown) perforated over itsentire expanse, behind which there is provided a pressureequalizingchamber (like the chambers 41 and 49) into which the cooling air may befed via a conduit such as 42 or 50.

The wall portions 52, 53 and 54 in the illustrated form are all providedwith respective sets of parallel rows of orifices 56, 57 and 58establishing communication between the plenum chamber 55 and the coolingchamber section bounded by the wall 52-53-54. In FIG. 5, each of thewall portions 53 and 54 is shown as being provided with three rows ofsuch orifices, while the wall portion 52 is shown as being provided withseven such rows, i.e., two pairs of rows juxtaposed to the generallocations of the shoulders of a tire to be cooled, one central rowjuxtaposed to the crown center of such tire, and two rows eachintermediate the central row and a respective one of the pairs ofshoulder rows. It will be understood, of course, that the number of suchrows of orifices in any of the wall portions 52, 53 and 54 of the member51 may be varied,

even to the point of complete elimination of one or more rows, asdesired or found necessary. In practice, therefore, the cooling chamberdefined by two members 51 when the same are in the closed position willbe provided with circular rows of orifices arranged to direct coolingair not only against the tread V of a tire received in said coolingchamber, but also against portions of the sidewalls of the tire, whichmay be advantageous, for example, in the case of relatively large sizetires having considerable masses of usually highly heat-retaining rubberextending from the tread and shoulder regions radially inwardly alongthe sidewalls.

As will be readily understood, the postinflation equipment 21 mayinclude two chucks 22 substantially identically arranged to cooperatewith a dual cavity press, and the jet air cooling apparatuscorrespondingly may include two cooling chamber arrangements 31-32 or51.

Although the jet air cooling apparatus so far described is of relativelysimple construction, it is believed that it does fully bring forth notonly the basic principles underlying the cooling aspects of the presentinvention but also the structural and operational features, parametersand relationships which will characterize any apparatus designed forthis purpose. Thus, one of the foundations of our invention is therecognition that even unrefrigerated air at the temperatures normallyreigning in tire curing rooms, generally between about 70 and 120 F.,will, if caused to flow at an appropriate rate as more fully describedhereinafter, deliver a heat transfer coefficient which is sufficientlyhigh to enable the required high heat transfer rate from a tire underpostinflation to be achieved with a degree of efficiency closelyapproximating that ofa cold water spray and many times that of ordinaryconvection air cooling. The term heat transfer coefficient" expressed inB.t.u./hr./sq. ft./ F. (where the last two terms refer, respectively, tothe surface area of the tire being cooled and the difference intemperature between the surface and the cooling air) is here used todescribe the effectiveness of the entire system the parameters of whichinclude the temperature, velocity and direction of the airflow as wellas the volume or mass rate of airflow, which in turn are functions ofsuch parameters as orifice design and size, percentage of open area, thecooling chamber size, and the gap between the orifices and the tiresurface. Basically, the higher the volume rate of flow and the velocityof flow, the higher is the heat transfer coefficient. Concomitantly,another foundation of our invention is the recognition that thepotential value of even such an airflow in effecting a uniform rapidcooling of a tire under postinflation, to the end of imparting theretocircumferentially uniform cure states, cord stress conditions anddimensional stability, will be lost if the direction, localization anddistribution of the airflow are not accurately defined to take intoaccount the fact that the distribution of the heat transfer coefficientover the tire surface must be coordinated with the thicknesses of thedifferent tire sections, to be higher at the thicker sections than atthe thinner ones.

On the basis of these considerations, we have determined thata jet aircooling apparatus according to our invention preferably should have thefollowing characteristics:

1. The air blower (i.e., 43 or its equivalent), which may be driven by aone to six-horsepower motor, should deliver the cooling air in thedesired temperature range at a static pressure of up to about seveninches of water.

2. The air distribution plate (i.e., 38 or 47 or the equivalent thereof)may be about Va and at most about Vz-inch thick and perforated withholes between about A and Ar-inch in diameter, spaced about inch apart,and providing between about 10 to 50 percent open area, and its designin cooperation with the design of the pressure equalizing region (i.e.,chamber 41 or 49 or the equivalent thereof) should be such as to developa uniform static air pressure in the distribution zone (chamber 37 or 46or the equivalent thereof) between about l-Vz and /2 inches of water. Itwill be understood that the plate thickness is not a critical parameterand need only be sufficient to provide the strength required forfabrication and to resist the fluid forces due to the airflow.

The cooling chamber boundary or air jet locus (i.e., wall 36-44 or theequivalent thereof) should be at most about %-inch thick and perforatedwith holes between about Va and %-inch in diameter providing betweenabout 1 :41. and 15 percent open area and enabling delivery, at a staticpressure between about 1 and 4 inches of water, ofa heat transfercoefficient between about 15 or 70 B.t.u./hr./sq. ft./ F., which we havedetermined requires a volume flow rate of between about 500 and 5,000 ormore cubic feet per minute, and the diameter of the chamber should besuch as to locate the air jets (i.e., the holes or openings 3945 orequivalents thereof) between about V2 and 5 inches from the tiresurface, thereby to enable each given chamber to be used in coolingtires of a range of'sizes. It should be understood that the orifices maybe in the form of round holes as stated or in the form of slots,nozzles,

etc.

4. The jet air cooling apparatus should be adapted to the particulartypes of postinflation equipment available. Thus, it may be designed ineither sectional or unitary form for cooling tires oriented either in asubstantially vertical plane or in a substantially horizontal plane orin an inclined plane, it may be arranged for rectilinear or arcuatemovement axially or radially relative to the tires, or it may bestationary for cooperation with movable postinflation equipment, etc.,or both may be movable.

As an example of the operation of the cooling process of our invention,in actual production runs utilizing a four-row A- inch orificearrangement apparatus of the type shown in FIGS. 1 to 4, with adjacentorifices at Vi-inch center to center spacings and the outside rows fiveinches apart, we have found that in the case of a 7.00 13/2 nylon tirecured in a Bag-O- Matic" press with a 215 lb. steam cure, an externalmold temperature of 324 F. and a total mold cycle of 13.5 minutes, jetair cooling during the postinflation cycle, with a pressure of threeinches of water at the cooling chamber and a delivered volume flow rateof 723 cubic feet per minute of air at 1 10 F., reduced thetread-carcass interface temperature to F. at the crown center of thetire in about nine minutes and at the relatively thicker shoulders inabout 12.2 minutes. In the case of an 8.25 14/2 nylon tire cured underidentical conditions with a 16.4 minutes mold cycle, the same jet aircooling during postinflation reduced the tread-carcass interfacetemperature to 160 F. at the crown center in about 10.3 minutes and atthe shoulders in about 14.3 minutes.

Merely by way of illustration of the jet air cooling of tires on othertypes of postinflation equipment, in the copending application of R.i-luHugger and R. J. Brown, Ser. No. 140,602, filed May 5, 1971, whichis a continuation of Application Ser.

No. 822,746, filed May 7, 1969 and now abandoned, which in turn is acontinuation of Application Ser. No. 596,122, now abandoned but filed ofeven date with the aforesaid Application Ser. No. 596,1 14, all of whichapplications are assigned to the same assignee as the instantapplication, there are disclosed other forms of apparatus adapted forthe practice of the jet air cooling aspects of the present invention.Thus, one such apparatus, shown in FIGS. 6 to 10 of the instantapplication and designated by the reference numeral 20a, is designed foruse in conjunction with quadruple postinflation equipment 21a (FIG. 6)provided with ,two dual chuck arrangements.

The postinflation equipment 210 per se, which is described andillustrated herein only to the extent of the basic elements thereof withwhich the jet air cooling apparatus 20a cooperates, in essence includesacolumn or stand 59 supported by a framework 60 located between the press(not shown) and a framework 61 which supports the apparatus 200 in amanner to be more fully described presently. The stand 59 is arrangedmidway between two roll conveyors 62, also supported by the framework60, on which the hot tires taken out of the mold are delivered to thepostinflation equipment. Two pairs of radially spaced chucks 63 and 64are supported in parallel relation by a fulcrum member 65 which in turnis sup ported by the stand 59 for rotation about a horizontal axis 66.Also secured to and extending upwardly from the stand 59 is doubleacting pneumatic cylinder 67 which is a part of the chuck-operatingmechanism of the postinflation equipment 21a. As to the operation of thelatter, it is deemed sufficient to point out that by suitable means,such as a rack and pinion combination (not shown), the fulcrum member 65can be reciprocally pivoted about the axis 66 so as to dispose eitherthe pair of chucks 63 or the pair of chucks 64 in the upper position.

The jet air cooling apparatus 20a provides two cylindrical coolingchambers C-1 and C-2 (FIGS. 6 and 9) each adapted to receive arespective chuck 63 or 64 (and tire supported thereby) when the pair ofsuch chucks is in the upper position. The chambers C-1 and C-2 aredefined within a pair of hollow cylindrical walls 68 and 69 extendingdownwardly from the bottom of a hollow box structure 70 which isprovided with a pair of rearwardly extending arms 71 (FIGS. 6, 7 andfixed at their outer ends to a cross shaft 72 joumaled in bearings 73atop horizontal side members 74 of the framework 61. Also fixedlyconnected with the cross-shaft 72 are two arms 75 which are articulatedto the free ends of respective piston rods 76 extending from a pair ofdouble acting fluid pressure cylinders 77 pivotally mounted at 78 on therear cross member 79 of the framework 61. Thus, upon actuation of thecylinders 77 to retract the piston rods 76, the box 70 with all partscarried thereby is raised into the broken line position thereof shown inFIG. 6, while upon actuation of the cylinders 77 to protract the pistonrods 76, the box 70 is lowered into its solid line position shown inFIG. 6, the rest position in this case being defined by a pair ofadjustable jacks or like abutments 80 mounted on the front member 81 ofthe framework 61 beneath a pair of brackets 82 carried by the arms 71.

Reverting now to the cooling structure of the apparatus a, the innermembers 68a and 69a of the cooling chamber-defining walls 68 and 69 areprovided with respective sets of rows of orifices 83 and 84corresponding, for example, in size and arrangement to the orifices 39and 45 of the apparatus 20 shown in FIGS. 1 to 4. The orifices 83 and 84establish communication between the chambers C-1 and C2 and the annularinterior plenum chambers 85 and 86 of the walls 68 and 69.

The plenum chambers 85 and 86 communicate with the interior of the box70 through respective sets of circularly arranged openings 87 and 88provided in the bottom wall 70a (FIG. 9) of the box. In the top wall 70bof the box just rearwardly of the front wall 70c thereof is provided arectangular opening 89 extending laterally and covered by a perforatedplate 90. Mounted atop the box 70 over the perforated distribution plate90 is an inverted funnel-shaped duct 91 which at its narrower upper endis connected to the discharge side of a blower 92 the intake side ofwhich is adapted to draw air from any suitable source as previouslyexplained, e.g., the ambient curing room atmosphere. The blower ismounted in any suitable manner atop the box 70 and is arranged to bedriven by means of an electric motor 93 (omitted from FIG. 8 for thesake of clarity) through the intermediary of a drivebelt 94 or otherappropriate transmission means. As indicated diagrammatically only inFIG. 8, a safety housing or cover 95 may be provided for the drivebelt.

Referring further to FIGS. 9 and 10 in particular, the box 70 istraversed from top to bottom by a pair of cylindrical ducts 96 and 97which are disposed essentially concentrically with the rings of openings87 and 88 in the bottom wall 70a of the box 70. At their upper ends theducts 96 and 97 communicate with the atmosphere, and at their lower endsthese ducts communicate with the cooling chambers C-1 and C-2. Inaddition, the box 70 is provided to the rear of the perforated plate 90and intermediate the rings of openings 87 and 88 with a substantiallyrectangular passageway 98 which extends from the top to the bottom ofthe box and, as clearly indicated in FIGS. 6, 7 and 8, is adapted toaccommodate the chuck-operating cylinder 67 of the postinflationequipment 21a.

For purposes of a description of the operation of this system, it isassumed as a starting condition that the postinflation treatment of twotires T-l and T-2 (FIGS. 6 and 7) supported on the upper chucks 63 is inprogress. The jet air cooling apparatus 20a thus is in its lowered orsolid line position, whereby the tires T-I and T-2 are disposed withinthe confines of the cooling chambers 01 and C-2, respectively. With theblower 92 working, (for example, a 19-inch wheel diameter, radial bladefan running at 1,7l8 r.p.m.) air at the ambient curing room temperature,say 100 F., passes through the duct 91 at a static pressure of about5-54 inches of water, and through the perforated distribution plate intothe interior of the box 70 where the pressure is about 4- /6 inches ofwater and from which it flows through the respective sets of openings 87and 88 into the annular plenum chambers 85 and 86, from which in turnunder a uniform static pressure of about 3-98 inches of water it entersthe cooling chambers C01 and G2 through the respective sets of orifices83 and 84 at the desired volume flow rate, say about 795 cubic feet perminute. As in the case of the previously described apparatus 20, thisair is directed to play principally against the tread in the shoulderregions of the tires T-l and T-2 and thence over both the crown centerregion and the sidewalls to effect the desired rapid cooling of thetires, a part of the spent air leaving the cooling chambers C-1 and C-2through the downwardly open ends thereof, and a part of the spent airleaving said chambers through the upper ends thereof via the cylindricalducts 96 and 97. The overall airflow pattern is indicated by the arrowsin FIG. 9. It is found that in the case of a 7.75Xl4/2 nylon-44 tiresubjected to a dual 300 lb./ lb. internal pressure steam cure with anexternal mold temperature of 326 F. in a 13.5 minutes mold cycle, thetemperature at the tread-carcass interface in the shoulder regions of aso-called tire is reduced to the range of ISO- F. in about l3 minutes.

Shortly prior to the termination of the concurrent mold cycle in thepress, the tires which were previously subjected to postinflation andcooled on the new lower chucks 64 are deflated and released from thelatter to drop onto the downwardly inclined roll conveyors 62, alongwhich they then travel to carry-off conveyor 99 located between the legs100 of the framework 61, as indicated diagrammatically by the dot-dashline tire T in FIG. 6. When the press is now opened at the end of thesaid concurrent mold cycle, the tires then being cured are removed fromthe press and transferred to the location of the postinflation equipment21a along the roll conveyors 62, as indicated diagrammatically by thedot-dash line tire T" in FIG. 6. These tires are picked up and mountedon the chucks 64 in any suitable manner, which need not be explained indetail, whereuponair is admitted thereinto to inflate the tires to thedesired pressure.

As soon as this condition has been attained, the cylinders 77 areactuated to retract the piston rods 76, thereby to swing the box 70 andappurtenant parts upwardly into the broken-line position thereof shownin FIG. 6. As the box 70 reaches this position, an arm 101 (FIGS. 7 and8) carried by the crossshaft 72 is caught by a latch 102 and at the sametime comes into engagement with the actuating lever 103a of a suitablecontrol switch 103, which causes the operating mechanism of thepostinflation equipment to be actuated so as to invert the chucks byappropriate movement of the fulcrum member 65 about its axis 66. Whenthis changeover is completed, which may be sensed, for example, by meansof a limit switch (not shown) associated with the fulcrum member 65, thelatch 102 is released and the cylinders 77 are reversely actuated toprotract the piston rods 76, thereby to swing the box 70 and associatedparts back down into the solid-line position thereof so as to cause thetires on the now upper chucks 64 to be disposed within the confines ofthe cooling chambers C-1 and C-2.

The cooling of these'tires then proceeds as previously explained for thetires T-l and T2, while the latter remain on the now lower chucks 63until shortly before the termination of the then new concurrent moldcycle in the press, at which lOIOZS. 0088 time they are deflated anddropped onto the conveyors 62 preparatory to the arrival of the nextpair of tires.

It is noted, in passing, that any tires, e.g., the tires T-1 and T- 2,which have been subjected to the jet air cooling operation in thechambers C-1 and C-2, will have reached their intended relatively lowtemperature of about l40-l60 F. in only one postinflation cycle, i.e., aperiod of time somewhat shorter than one full mold cycle, Theoretically,of course, they need not be kept on the now lower chucks for thedescribed longer period of time amounting to almost two full moldcycles, but could be deflated and removed from the chucks substantiallyimmediately after the latter are shifted from the upper or coolingposition into the lower or discharge position. In actual practice,however, it is highly recommended that the tires be retained on thelower chucks as described, since this extra cooling period is found tohave an appreciably beneficial effect on the road lift of the tires. Atthe same time, no adverse effects result from the continued open airconvection cooling of these tires during this period, since the curestates and the carcass cord shrinkage stresses had already reached suchlevels during the jet air cooling stage that any changes which mightstill take placein these conditions are negligible for all practicalpurposes.

Although in the preferred so far described apparatus forms, theairflowis initially such as to impinge in the first instancesubstantially, radially against selected regions of the tread of thetire being cooled, whereupon the air flows essentially laterally overthe tread and ultimately out of the cooling chamber, our objectives canbe attained as well by other types of apparatus providing the necessarycooling zone and a controlled airflow, subject to the fundamentalrequirement that the cooling air deliver a heat transfer coefficient (asherein defined) of the required magnitude.

Merely by way of example, as diagrammatically shown in FIGS. 11 to 13 inthe case of an apparatus 20b (of the class illustrated in FIGS. 1 to 4designed for cooperation with postinflation equipment 21), the airflowinto the cooling chamber defined by the two relatively seperable members31a and 32a is initially directed obliquely relative to the outersurface of the tread of the tire T then undergoing postinflation, theair as before entering at a plurality of circumferentially spacedlocations. The resultant airflow in the cooling chamber thus has acircumferential circulatory component, as indicated by the arrows inFIG. 13, spent air again ultimately escaping laterally of the tire.

Although various ways to achieve this condition are available, thepreferred construction we have illustrated comprises, for each of themembers 31a and 32a, a channel-shaped arcuate housing 104 which is openat its circularly curved radially inward side and closed at itsvaryingly curved radially outward side. Welded or otherwise suitablyaffixed to the inner surfaces of the two side walls 105 and 106 of thehousing 104 at a uniform distance from the radially inwardmost edgesthereof is a circularly curved plate 107 provided with a plurality ofspaced, transverse, parallel rows of openings 108. Each such row ofopenings establishes communication between the plenum chamber 109,defined at the radially outward side of the plate 107 within the housing104, and a respective one of a set of flat nozzles 110, each of thelatter being defined by a respective pair of spaced plates 111 welded orotherwise suitably secured to the radially inward side of the plate 107and to the sidewalls 105 and 106 of the housing 104. As before, thecooling air is admitted into the plenum chambers 109 from the blower 43via respective ducts 42a and 50a.

The cooling air thus leaves the plenum chambers in the form of aplurality of fiat jets. In this type of arrangement, the locus of thedischarge ends of the nozzles 110 is symmetrically concentric to thetire being cured and constitutes the effective boundary of the coolingchamber, but it will be understood that this locus need not becylindrical as shown but could be transversely arcuate, e.g., concavetoward the tread of the tire,

through appropriate curvature of the discharge end edges of a the pairsof nozzle-defining plates 111. v

Alternatively, as diagrammatically shown in FIG. 14 in the case of a jetair cooling apparatus 200 designed for cooperation with postinflationequipment 21b, the airflow into the cooling chamber defined between twoaxially relatively separable members 112 and 113 of the apparatus 20c isinitially directed countercurrently against the tire under postinflationfrom the opposite sides of the tread thereof. The main part of thecooling air from each such member thus flows over the tread toward thecrown center of the same, ultimately escaping radially of the tire,while a minor part of the cooling air from each member flows over therespective sidewall, ultimately escaping at the bead region of the tire.

Again, various ways of achieving't his condition are availa ble. Thepreferred construction we have illustrated makes use of postinflationequipment having a stationary chuck structure 114 and a relativelymovable chuck structure 115. The support 116 for the stationary chuckstructure, which accommodates the air conduit means 117 for inflatingthe tire T to be cooled, also carries the member 112 of the jet aircooling apparatus 200. The member 112 is in the shape of an annularhousing defining an inner plenum chamber 118 and a surroundingdistribution chamber or zone 119 separated by a perforated distributionplate 120. Similarly, thesreciprocally displaceable support 121 for themovable chuck structure also carriesthe member 113 which issubstantially identical in shape with member 1 12 and defines an innerplenum chamber 122 and an outer distribution chamber or zone 123separated by a perforated distribution plate 124. Cooling air isadmitted into the two zones or chambers 119 and 123 via preferablyflexible ducts 125 and 126 connected to the discharge side of a suitableblower (not shown) or other air source, and preferably annular orifices127 and 128 are provided at the appropriate locations in the respectivemated walls 118a and 12211 of the members 112 and 113, which define theboundary of the cooling chamber, to enable the cooling air to enter thelatter from the plenum chambers 118 and 122 in the form of a pair ofannular jets.

It will be apparent, of course, that still other airflow patterns andconditions. as well as other air jet configurations and orientationswhich achieve the desired cooling rates and uniformity of tirecharacteristics, could be devised and utilized in lieu of those so fardescribed, for example incorporation of circumferential airflow in theapparatus of FIGS. 6 to 10.

The jet air cooling of tires while under postinflation in accordancewith the principles of the present invention, independently of thenature of the airflow utilized, in addition of providing uniform coolingand appreciably shortening the required postinflation cycles, leads toanother extremely important advantage in the manufacture of tires, towit it makes possible a concomitant shortening of the mold cycles insuch a manner that the feasibility of producing optimally cured tiresremains unimpaired despite the shortened overall cure cycles and theconsequent increased production rate. In general, this result isachieved by utilizing the external mold temperatures in the press toheat the tires during the mold cycles to such an extent as to ensureattainment of a predetermined state of cure of the rubber, at all pointsgenerally in excess of 50 percent but less than 100 percent of the totalcure state desired to be achieved during the total cure cycle, beforethe. postinflation cycle begins. The significance of this procedure andits relationship to the subsequent jet air cooling operation during thepostinflation cycle will be clearly understood from the following,reference in this connection being had to FIG. 15 of the drawings.

In FIG. 15 the curves X, Y and Z graphically represent three plots ofcure rate against time (the reference points are at the center of theshoulder section of the tread, approximately midway between the outertread surface and the band ply, but the same considerations would applyfor any other reference point) for three identical tires, subjectedduring otherwise identical curing operations to three different externalmold temperatures 6, 0' and 9". By virtue of the nature of the plot,therefore, the area under each curve represents the total cure Inlnnlstate reached by the respective tire, expressed in arbitrary cure unitswhich need not be uniquely defined for the purpose of the presentdiscussion. (ln one segment of the tire industry, for example, 1 cureunit is defined as the state of cure achieved by the rubber material inthe period of one'minute at an arbitrarily selected referencetemperature.) It is to be as sumed, however, that at the three endpoints X-l, Y-l and Z- 1, representing the times when the postinflationoperation is terminated, the three tires all have identical cure statesof 72 units, i.e., the areas under the respective curves are equal.

Referring now first to the curve X, the same represents a standardcuring and postcure inflation cooling operation. Starting at time 0, thecure of the tire proceeds with a conventional external mold temperature,6, continuing to the point X-2 which is reached after about 20 minutesand corresponds to the release of pressure in the bladder of the press(usually less than /2 minute before the-press is opened). At that time,the cure of the tire has progressed about halfway to its intended endpoint, the area below the curve X to the left of the vertical linepassing through the point X-2 being equal to 35.5 cure units, i.e., ashade less than one-half of the desired final cure.

The tire is then mounted and inflated on the postinflatlon equipment andpermitted to cool by open air natural convection, which proceeds at arelatively low rate for a further period of about 20 minutes until atpoint X-l the tire has reached the desired cure state of 72 cure units.It will be understood that the reason for the curve X flattening out asit approaches point X-l is that over the last several minutes of thecooling period, the cure rate drops almost to zero since the tire isalready at a relatively low temperature, say in the neighborhood ofabout 200 F. In any event, it is readily apparent that under this methoda substantial part (actually more than 50 percent) of the desired curestate of the tire in achieved after the pressure is released in thebladder and the tire taken out of the mold, and since, as previouslypoint cut, open air natural convection cooling in a tire curing roomcannot possible be uniform around the circumference of the tire, theexact state of cure at all points of the tire is not properlycontrolled. The result is a tire which is more likely than notcharacterized by excessive dimensional instability, i.e.,circumferential nonuniformity of radial dimension, as well as bycircumferentially nonuniform cure states and, in the case of a tirereinforced by a carcass of heat-shrinkable fiber tire cords, also bycircumferentially nonuniform cord stress conditions.

This deficiency in the known tire manufacturing operation is effectivelyeliminated by our invention, since by virtue of the markedly superiorefficiency of our jet air cooling process we are now able to precede thepostinflation cycle with a mold cycle in which the rubber portions ofthe tire are raised to a much higher than usual temperature. As aresult, we are able to ensure that a major portion, generally within therange mentioned above and preferably on the order of about 65 to 75percent, of the desired cure state is achieved in a shorter time in themold under the precisely controlled conditions existing therein, andthat the remaining minor portion of the desired cure state achieved outof the mold is also brought about in a shorter time as well as underprecisely controlled conditions so as to be circumferentially uniform atany given radial dimension of the tire.

These advantages of our invention are clearly illustrated by the curvesY and Z in FIG. 15, the former representing a tire cure utilizing anexternal mold temperature 6 somewhat higher than the conventiona moldtemperature 6 and followed by jet air cooling of the tire duringpostinflation, and the latter representing a tire cure utilizing an evenhigher external mold temperature followed by an appropriately higherrate of jet air cooling. Thus, the temperatures 0 and 0" are such thatafter periods of only about 17 and 13.5 minutes the areas under thecurves Y and Z to the left of the vertical lines passing through thepoints Y-2 and 2-2 are equal to 48.5 and 51 cure units, respectively,clearly major proportions of the desired cure states of 72 units.Accordingly, the states of cure at the start of the subsequent jet aircooling operations are such that the desired cure states of 72 units arereached, and the postinfiation cycles can be terminated, at points Y-!and 2-1 after only 13 and 7- /5 minutes, respectively, following therelease of pressure in the bladder.

It will be readily apparent, therefore, that the implementation of ourinvention as aforesaid is not only conductive to the production of moretires which are characterized by circumferentially substantially uniformthermal, physical and geometrical properties to a high degree, but alsoenables both the mold and postinflation cycles, and thus the overallcuring cycles, to be substantially shortened, whereby the achievement ofmajor economics in tire manufacture becomes a realizable goal.

in the preceding discussion, the indicated cure state is taken to bethat at the thickest parts of the tire, which generally means the treadin the shoulder regions of the tire. The implementation of the presentinvention, however, automatically results in the achievement of optimumcure states at other, thinner parts of the tires as well, since the jetair cooling conditions would normally have been first properlypredetermined, adjusted and optimized, with due consideration given tosuch factors as air temperature and velocity, orifice size anddistribution and arrangement, tire size and type and temperature.duration of the mold and postinflation cycles, and others not necessaryto reiterate and itemize in detail at this point, to take the thicknessvariations into account, i.e., to ensure that even though a thinner partwould have been cured to a greater extent during the mold cycle than athicker part, the airflow distribution and the changes in thetemperature of the air as it flows across the thick and thin parts aresuch that at the end of the postinflation cycle the thin parts reachtheir optimum state of cure at substantially the same time as the thickparts.

It is to be understood that the foregoing description of preferredapparatus and process aspects of the present invention is for purposesof illustration only, and that the structural and operational features,characteristics and relationships disclosed herein may be changed andmodified in a number of ways, as, for example, by the substitution ofdual units for single units and vise versa, none of which entails adeparture from the spirit and scope of the present invention as definedin the hereto appended claims.

Having thus described our invention, what we claim and desire to secureby Letters Patent is as follows:

1. Apparatus for postmold cycle cooling a pneumatic tire, after theremoval of the tire from the mold and during the course of apostinflation treatment, by means of a mass of cooling air moving underflow conditions sufi'lcient, at the temperature of said cooling air, toachieve over the surface of the tire a tire to air heat transfercoefficient ranging from about 15 to about B.t.u./hr./sq. ft./ F. and toensure that the ultimate cooled tire is characterized by an optimum setof circumferentially substantially uniform thermal, physical andgeometrical properties, comprising:

a. means defining a cooling zone within the confines of which the tireto be cooled may be axially received;

b. said means defining said cooling zone including wall means 1.encircling and constituting the peripheral boundary of said cooling zoneand 2. arranged in juxtaposition to the mounting location of apostinfiation chuck on which the tire is mounted while undergoing saidpostinflation treatment;

c. means providing a flow of cooling air against and over the entiresurface of said wall means facing away from said cooling zone; and

. orifice means provided in said wall means coextensively with saidperipheral boundary of said cooling zone and establishing airflow pathsinto said cooling zone from the surrounding region contiguous to saidsurface of said wall means;

e. said orifice means being positioned for directing said cooling air 1.in jet form into said cooling zone the entire peripheral boundary 2.simultaneously along thereof and 3. so as to be incident initiallyagainst the tread of the postinfiated tire being cooled, in at least theshoulder regions of the tread, simultaneously along the entirecircumference of the tire when the same is received within said coolingzone;

f. said orifice means being constructed and arranged to pro.

vide a percentage of open area in said wall means coordinated with theoperational characteristics of said airflow providing means to ensurethe existence of said sufficient flow conditions in said cooling zone.

2. Apparatus according to claim 1, said orifice means comprising aplurality of orifices having a locus which in said cooling zone liesbetween about A and 5 inches from the exterior surface of the tread ofany size tire to be cooled when the same is received in said coolingzone.

3. Apparatus according to claim 2, said orifices being arranged in twopairs of parallel rows located opposite the respective locations of thetread of the tire in the shoulder regions thereof when the same isreceived within said cooling zone.

I 4. Apparatus according to claim 3, said orifices being of circularconfiguration and each being between about Va and 56- inch in diameter,and the centers of directly adjacent orifices in each pair of rows beingbetween about A and 1 inch apart.

5. Apparatus according to claim 1, said means defining said cooling zonecomprising a pair of arcuate wall sections the concave front faces ofwhich are directed toward each other, said wall sections being arrangedfor relative approaching and separating motion and when in closed end toend juxtaposition constituting the peripheral boundary of said coolingzone, and said orifice means being provided as adjuncts of said wallsections.

6. Apparatus according to claim 5, each of said wall sections '35 witheach half of said distribution zone via said inlet opening,

and the intake side of which is open to the curing room temperature.

8. Apparatus according to claim 6, further comprising blower means thedischarge side of which is in communication with each half of saiddistribution zone via saidinlet opening, and the intake side of which isopen to the atmosphere outside the curing room.

9. Apparatus according to claim 6, further comprising blower means thedischarge side of which is in communication with each half of saiddistribution zone via said inlet opening, and the intake side of whichis in communication with a source of cooling air at a temperature belowabout 1 20 F.

10. Apparatus according to claim 6. each of said hollow bodiescomprising an internal wall structure dividing the respective halfdistribution zone defined within that body into a plenum chamber locatedto one side of said internal wall structure and coextensively contiguousto both the associated wall section and said internal wall structure,and into a distribution chamber located to the other side of saidinternal.

in row in the otherwall section.

%3. Apparatus according to claim 12, said wall sections being bounded attheir respective opposite sides by corresponding pairs of radiallyinwardly and axially outwardly oriented lateral wall portions.

14. Apparatus according to claim 13, each of said lateral wall portionsbeing provided with at least one row of orifices, and each row in eachlateral wall portion of each wall section being aligned with acorresponding row in the corresponding lateral wall portion of the otherwall section.

15. Apparatus according to claim 5, said orifice means comprising aplurality of flat nozzles extending at uniform spacing codirectionallyobliquely inwardly relative to the concave front faces of said wall.sections and being oriented codirectionally nonradially of the tread ofthe tire being cooled when the same is received in said cooling zone.,

16. Apparatus according to claim 5, said orifice means comprising a pairof annular openings arranged in the laterally out wardmost regions ofsaid wall sections so as to be located adjacent the shoulders of thetire being cooled when the same is received in said cooling zone.

17. Apparatus according to claim 5, said orifice means comprising aplurality of orifices in said wall sections sufficient to providebetween about 1%, and 15 percent open area in the total area of saidwall sections.

mun: rinor g TE snares PATENT omen PO-l-OSO QERTEFEQATE 0F P tentNO.3,645,660 Dated F r ary 9, 1972 Inventor( Richard H, Hugger and GeorgeC. Huang It is certified that error appears in the above-identifiedpatent and that said Letters Patent are hereby corrected as shown below:

r Column 1, line 7 1, for "by" read to-=- Column 6, line 28, .1

for "at" (second occurrence) read in, Column 10, line 17, for "CO1" read--C-l- -e Column 10, line 34, for "so-called" read --so-coo1ed--, Column13 line 35, for "in" read --is--. Column 13, line 37, for "point read--pointed--., Column 13, line 39, for "possible" read ---possibly--.Column 1 1, line 7, for "conductive" read conducive---a Column 1 1, line13, for "economics" read --econom1es-- Column 15, lines 15/46, for"temperature" read atmosphere--. Column 16, line 23, for "of wallsections" read "of said wall sections--.

Signed and sealed, this 9th day of January 1973.

(SEAL) Attest:

EDWARD M.FLETCHER,JR. ROBERT GOTTSCHALK Attesfcing Officer Commissionerof Patents

1. Apparatus for postmold cycle cooling a pneumatic tire, after theremoval of the tire from the mold and during the course of apostinflation treatment, by means of a mass of cooling air moving underflow conditions sufficient, at the temperature of said cooling air, toachieve over the surface of the tire a tire to air heat transfercoefficient ranging from about 15 to about 70 B.t.u./hr./sq. ft./* F.and to ensure that the ultimate cooled tire is characterized by anoptimum set of circumferentially substantially uniform thermal, physicaland geometrical properties, comprising: a. means defining a cooling zonewithin the confines of which the tire to be cooled may be axiallyreceived; b. said means defining said cooling zone including wallmeans
 1. encircling and constituting the peripheral boundary of saidcooling zone and
 2. arranged in juxtaposition to the mounting locationof a postinflation chuck on which the tire is mounted while undergoingsaid postinflation treatment; c. means providing a flow of cooling airagainst and over the entire surface of said wall means facing away fromsaid cooling zone; and d. orifice means provided in said wall meanscoextensively with said peripheral boundary of said cooling zone andestablishing airflow paths into said cooling zone from the surroundingregion contiguous to said surface of said wall means; e. said orificemeans being positioned for directing said cooling air
 1. in jet forminto said cooling zone
 2. simultaneously along the entire peripheralboundary thereof and
 3. so as to be incident initially against the treadof the postinflated tire being cooled, in at least the shoulder regionsof the tread, simultaneously along the entire circumference of the tirewhen the same is received within said cooling zone; f. said orificemeans being constructed and arranged to provide a percentage of openarea in said wall means coordinated with the operational characteristicsof said airflow providing means to ensure the existence of saidsufficient flow conditions in said cooling zone.
 2. arranged injuxtaposition to the mounting location of a postinflation chuck on whichthe tire is mounted while undergoing said postinflation treatment; c.means providing a flow of cooling air against and over the entiresurface of said wall means facing away from said cooling zone; and d.orifice means provided in said wall means coextensively with saidperipheral boundary of said cooling zone and establishing airflow pathsinto said cooling zone from the surrounding region contiguous to saidsurface of said wall means; e. said orifice means being positioned fordirecting said cooling air
 2. simultaneously along the entire peripheralboundary thereof and
 2. Apparatus according to claim 1, said orificemeans comprising a plurality of orifices having a locus which in saidcooling zone lies between about 1/2 and 5 inches from the exteriorsurface of the tread of any size tire to be cooled when the same isreceived in said cooling zone.
 3. Apparatus according to claim 2, saidorifices being arranged in two pairs of parallel rows located oppositethe respective locations of the tread of the tire in the shoulderregions thereof when the same is received within said cooling zone. 3.so as to be incident initially against the tread of the postinflatedtire being cooled, in at least the shoulder regions of the tread,simultaneously along the entire circumference of the tire when the sameis received within said cooling zone; f. said orifice means beingconstructed and arranged to provide a percentage of open area in saidwall means coordinated with the operational characteristics of saidairflow providing means to ensure the existence of said sufficient flowconditions in said cooling zone.
 4. Apparatus according to claim 3, saidorifices being of circular configuration and each being between about1/8 and 3/8 -inch in diameter, and the centers of directly adjacentorifices in each pair of rows being between about 1/2 and 1 inch apart.5. Apparatus according to claim 1, said means defining said cooling zonecomprising a pair of arcuate wall sections the concave front faces ofwhich are directed toward each other, said wall sections being arrangedfor relative approaching and separating motion and when in closed end toend juxtaposition constituting the peripheral boundary of said coolingzone, and said orifice means being provided as adjuncts of said wallsections.
 6. Apparatus according to claim 5, each of said wall sectionsconstituting a part of a respective hollow body which defines arespective half of an air distribution zone coextensive with the convexrear face of the respective wall section and in communication with saidorifice means, and each of said hollow bodies being provided with aninlet opening for admitting cooling air into said distribution zone. 7.Apparatus according to claim 6, further comprising blower means thedischarge side of which is in communication with each half of saiddistribution zone via said inlet opening, and the intake side of whichis open to the curing room temperature.
 8. Apparatus according to claim6, further comprising blower means the discharge side of which is incommunication with each half of said distribution zone via said inletopening, and the intake side of which is open to the atmosphere outsidethe curing room.
 9. Apparatus according to claim 6, further comprisingblower means the discharge side of which is in communication with eachhalf of said distribution zone via said inlet opening, and the intakeside of which is in communication with a source of cooling air at atemperature below about 120* F.
 10. Apparatus according to claim 6, eachof said hollow bodies comprising an internal wall structure dividing therespective half distribution zone defined within that body into a plenumchamber located to one side of said internal wall structure andcoextensively contiguous to both the associated wall section and saidinternal wall structure, and into a distribution chamber located to theother side of said internal wall structure and coextensively contiguousto the latter, each of said internal wall structures being provided witha respective plurality of apertures establishing communication betweenthe associated distribution and plenum chambers, and each of said inletopenings being in communication with the associated distributionchamber.
 11. Apparatus according to claim 6, said wall sections beingsemicylindrical in shape.
 12. Apparatus according to claim 11, saidorifice means comprising at least one row of orifices in each of wallsections, each row in each wall section being aligned with acorresponding row in the other wall section.
 13. Apparatus according toclaim 12, said wall sections being bounded at their respective oppositesides by corresponding pairs of radially inwardly and axially outwardlyoriented lateral wall portions.
 14. Apparatus according to claim 13,each of said lateral wall portions being provided with at least one rowof orifices, and each row in each lateral wall portion of each wallsection being aligned with a corresponding row in the correspondinglateral wall portion of the other wall section.
 15. Apparatus accordingto claim 5, said orifice means comprising a plurality of flat nozzlesextending at uniform spacing codirectionally obliquely inwardly relativeto the concave front faces of said wall sections and being orientedcodirectionally nonradially of the tread of the tire being cooled whenthe same is received in said cooling zone.
 16. Apparatus according toclaim 5, said orifice means comprising a pair of annular openingsarranged in the laterally outwardmost regions of said wall sections soas to be located adjacent the shoulders of the tire being cooled whenthe same is received in said cooling zone.
 17. Apparatus according toclaim 5, said orifice means comprising a plurality of orifices in saidwall sections sufficient to provide between about 1 1/4 , and 15 percentopen area in the total area of said wall sections.